So..

1)  From BS9000 to BC9500....a 5 pin connector so I can get auxilary sound going to and from....that would plug into the "TAPE" sockets of each??

This cable, yes..    http://cgi.ebay.com/DIN-5pin-Male-to-Male-for-Bang-Olufsen-and-others-L-K_W0QQitemZ160143329416QQihZ006QQcategoryZ64591QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

yes that will do it, but if you go for the data link cable instead. you always can use it to link something together, if you change your setup

Great Stig...so the 7 pin Datalink cable will work....no problems???

yes